Linke Turbidity Factor - World Maps

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These files were created in Feb. 2002 jointly by:

Each ´zip´ file contains a trimester of worldwide maps of Linke turbidity factor in tif format, given by latitude and longitude. Latitude is positive North, longitude is positive eastwards of longitude 0. The binary file is structured as follow :

• no header
• 2160 rows
• 4320 columns
• unsigned int encoding (1 byte per value)
• Upper left corner is 90 N, 180 W. Then, point 90 N, 179°5' W etc. Lower right is 90S 180 E.

The Linke turbidity factor has no unit. It typically ranges between 3 (clear skies) to 7 (heavily polluted skies). The factor was multiplied by 20 for storage. A value of 70 means a Linke turbidity factor equal to 3.5.

With a few Matlab commands, the january tif map can be geolocalized resulting in the following illustration:

January worldwide map of the Linke turbidity factor geolocalized in agreement with the file information. Philippe Blanc, Mines ParisTech.

Linke turbidity factor results from SoDa activities: fusion of ground measurements and gridded data (clearsky radiances, Water Vapour, aerosol optical depth, elevation).

The way of constructing the database is explained on the Web site HelioClim.

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